From ae1e40b3291149046d9ced3b19c774da6b30594d Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Thu, 5 Aug 2021 14:35:34 -0700
Subject: [PATCH] Enable /proc/diskstats for zvols

The /proc/diskstats accounting needs to be explicitly enabled
for block devices which do not use multi-queue.

Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #12440
Closes #12066
---
 module/os/linux/zfs/zvol_os.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c
index 8b29d73a3e..c174234263 100644
--- a/module/os/linux/zfs/zvol_os.c
+++ b/module/os/linux/zfs/zvol_os.c
@@ -837,6 +837,9 @@ zvol_alloc(dev_t dev, const char *name)
 	/* Disable write merging in favor of the ZIO pipeline. */
 	blk_queue_flag_set(QUEUE_FLAG_NOMERGES, zso->zvo_queue);
 
+	/* Enable /proc/diskstats */
+	blk_queue_flag_set(QUEUE_FLAG_IO_STAT, zso->zvo_queue);
+
 	zso->zvo_queue->queuedata = zv;
 	zso->zvo_dev = dev;
 	zv->zv_open_count = 0;